Touch sensor devices (also commonly called touch pads) are widely used in a variety of electronic systems. A touch sensor device is typically a sensitive surface that uses capacitive, resistive, inductive, optical, acoustic or other technology to determine the presence, location and or motion of one or more fingers, styli, and/or other objects. The touch sensor device, together with a finger or other object provides an input to the electronic system. For example, touch sensor devices are used as input devices for computers, such as notebook computers.
Touch sensor devices are also used in smaller devices, such as personal digital assistants (PDAs) and communication devices such as wireless telephones and text messaging devices. Increasingly, touch sensor devices are used in multimedia devices, such as CD, DVD, MP3 or other media players. Many electronic devices include a user interface, or UI, and an input device for interacting with the UI. A typical UI includes a screen for displaying graphical and/or textual elements. The increasing use of this type of UI has led to a rising demand for touch sensor devices as pointing devices. In these applications the touch sensor device can function as a cursor control device, selection device, scrolling device, character/handwriting input device, menu navigation device, gaming input device, button input device, keyboard and/or other input device.
Past designs of touch pads have had several notable limitations. One limitation has been the relative inflexibility of some designs to conform to the limited spaces available in some applications. For example, some designs have required large and inflexible circuit boards that prevented the touch pad from being used in small, low profile, or irregular spaces. One other notable limitation has been the cost of some previous designs. For example, some designs have relied exclusively on high cost materials for the substrates in the touch pads. The extensive use of these materials can be cost prohibitive for some applications. Finally, some previous designs have had limited long term reliability.
Therefore what is needed is an improved touch sensor device design that provides space flexibility and reliability without excessive device cost.